1. Technical Field
The present invention relates to a thermal printer that can avoid or reduce paper jams and other problems that are difficult to correct as a result of recording paper leaving the paper transportation path after passing the printing position.
2. Related Art
Recording paper is printed in a thermal printer by pressing the recording paper against a thermal head by means of a platen roller at a printing position located along the paper transportation path. In the thermal printer described in Japanese Unexamined Patent Appl. Pub. JP-A-2008-30301, the thermal head is carried on a head mounting plate that can move to and away from the platen roller, and contact pressure is held between the thermal head and platen roller as a result of the head mounting plate being urged to the platen roller side by a compression coil spring.
After the recording paper passes the printing position in this type of thermal printer, the front surface that was printed on is guided by a front guide member fastened beside the head mounting plate on the downstream side in the transportation direction, the back side is guided by a back guide member fastened beside the platen roller on the downstream side in the transportation direction, and the paper is thus conveyed in the transportation direction to the paper exit. A gap must be provided between the head mounting plate and the front guide member so that there is no interference with the front guide member when the head mounting plate moves. A gap must also be provided between the platen roller and the back guide member so that there is no interference with the back guide member when the platen roller rotates. As a result, the recording paper could enter either of these gaps after passing the printing position and cause a jam at a position outside the paper transportation path where fixing the paper jam is difficult.